Bonding apparatus for liquid crystal display device and method for manufacturing the same

ABSTRACT

An apparatus for manufacturing a liquid crystal display device includes a vacuum processing chamber having a substrate entrance, an upper stage and a lower stage provided at an interior of the vacuum processing chamber, and a compensation system positioned within the vacuum processing chamber for compensating for a temperature loss of the vacuum processing chamber when a pressure in the interior of the vacuum processing chamber is reduced.

[0001] The present invention claims the benefit of Korean PatentApplication Nos. 2002-15951 filed in Korea on Mar. 25, 2002, and2002-13191 filed in Korea on Mar. 12, 2002, which are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a manufacturing apparatus andmanufacturing method, and more particularly, to an apparatus and methodfor manufacturing a liquid crystal display (LCD).

[0004] 2. Discussion of the Related Art

[0005] In response to an increasing demand for displays devices havingdifferent operational characteristics, various display devices have beendeveloped including liquid crystal displays (LCD), plasma display panels(PDP), electro-luminescent displays (ELD), and vacuum fluorescentdisplays (VFD) to replace conventional cathode ray tube (CRT) devices.In particular, LCD devices are commonly used because of their highresolution, light weight, thin profile, and low power consumption. Inaddition, LCD devices are commonly implemented in mobile displaydevices, such as monitors for notebook computers, and display monitorsfor computers and televisions. Accordingly, efforts to improve imagequality of LCD devices have directly conflicted with the benefits oftheir high resolution, light weight, thin profile, and low powerconsumption. Thus, to incorporate LCD devices as general image displaydevices, image quality must be maintained.

[0006] Methods for manufacturing an LCD device may be divided twodifferent categories: liquid crystal injecting and liquid crystaldropping. The liquid crystal injecting method includes steps of forminga sealant pattern on a first substrate to form an injection inlet,bonding the first to a second substrates in a vacuum state, andinjecting liquid crystal material through the injection inlet. Theliquid crystal dropping method, which is disclosed in Japanese PatentApplication Nos. 11-089612 and 11-172903, includes steps of droppingliquid crystal material on a first substrate, arranging a secondsubstrate over the first substrate, and joining the first and secondsubstrates, thereby bonding the first and second substrates in a vacuumstate. Compared to the liquid crystal injection method, the liquidcrystal dropping method is advantageous since various steps, such asforming the liquid crystal material injection inlet, injecting theliquid crystal material, and sealing of the injection inlet may beomitted.

[0007]FIG. 1A is a cross sectional view of a substrate bonding deviceduring a loading process according to the related art. In FIG. 1A, thesubstrate bonding includes a frame 10, an upper stage 21, a lower stage22, a sealant dispenser (not shown), a liquid crystal material dispenser30, an upper chamber unit 31, a lower chamber unit 32, a chamber movingsystem, a receiving system, and a stage moving system.

[0008] The chamber moving system includes a driving motor 40 driven toselectively move the lower chamber unit 32 to a first location wheredeposition of the sealant and/or the liquid crystal material occur. Thedriving motor also is driven to move the lower chamber unit 32 to asecond location where the bonding process is performed.

[0009] The stage moving system includes another driving motor 50 drivento selectively move the upper stage 21 in a vertical direction. Thedriving motor moves the upper stage 21 in a downward direction during abonding process, and moves the upper stage 21 along an upward directionduring a loading/unloading process.

[0010] The receiving system temporarily receives an upper substrate,which is attached to the upper substrate to the upper stage 21, at bothdiagonal portions of the upper substrate. The receiving system includesa rotational axis 61, a rotational actuator 63, an elevating actuator64, and a receiving plate 62.

[0011]FIG. 1B is a cross sectional view of the substrate bonding deviceaccording to the related art during a bonding process. A process ofmanufacturing a liquid crystal display device using the substratebonding device according to the related art will be described withregard to FIG. 1B. In FIG. 1B, a second substrate 52 is loaded andaffixed onto the upper stage 21 by a vacuum chuck, and a first substrate51 is loaded and affixed onto the lower stage 22 by a vacuum chuck.Then, the lower chamber unit 32 having the lower stage 22 is moved froma loading/unloading position to the first location by the chamber movingsystem 40 for sealant and/or liquid crystal material deposition. Next,the lower chamber unit 32 is moved from the first location to the secondlocation by the chamber moving system 40 in preparation for bonding ofthe first and second substrates 51 and 52 by the chamber moving system40 after the sealant and/or liquid crystal material have been depositedonto the first substrate 51 by the liquid crystal dropping dispenser.Thereafter, the upper and lower chamber units 31 and 32 are positionedby the chamber moving system 40 and joined together to form a closedprocessing chamber. Next, the elevating and rotational actuators 64 and63 are driven so that the receiving plate 62 is positioned at two edgesof the second substrate 52 affixed to the upper stage 21.

[0012]FIG. 2 is a perspective view of a receiving system according tothe related art. In FIG. 2, the second substrate 52 is allowed to droponto each of the receiving plates 62 of the receiving system byreleasing of the vacuum chuck, and pressure at an interior of theprocessing chamber is reduced by a vacuum device 70 (in FIG. 1B). When avacuum state is achieved inside the processing chamber, the secondsubstrate 52 is affixed to the upper stage 21 by an electrostatic forceapplied to the upper stage 21, and the first substrate 51 is affixed tothe lower stage 22 by an electrostatic force applied to the lower stage22. In addition, the rotational and elevating actuators 63 and 64 (inFIG. 1B) of the receiving system are driven to prevent the receivingplate 62 and the rotational axis 61 from interfering with bonding of thefirst and second substrates 51 and 52. Finally, the upper stage 21 ismoved downward by the stage moving system 50 (in FIG. 1B) while in thevacuum state to closely fasten the second substrate 52 to the firstsubstrate 51.

[0013] However, the substrate assembly device according to the relatedart has the following limitations. Since the interior of the processingchamber is in the vacuum state during bonding of the first and secondsubstrates 51 and 52, a temperature in the interior of the processingchamber abruptly drops and any ambient moisture within the processingchamber condenses upon surfaces within the processing chamber. For thesereasons, the liquid crystal material and/or the sealant may peel wayfrom the first substrate 51, resulting in a defective substrateassembly.

SUMMARY OF THE INVENTION

[0014] Accordingly, the present invention is directed to a substratebonding apparatus for a liquid crystal display device that substantiallyobviates one or more problems due to limitations and disadvantages ofthe related art.

[0015] An object of the present invention is to provide a substratebonding apparatus using a liquid dropping method that compensates aninterior temperature of a processing chamber of the substrate bondingapparatus to prevent condensation of moisture in the processing chamber.

[0016] Additional features and advantages of the invention will be setforth in the description which follows, and in part will be apparentfrom the description, or may be learned from practice of the invention.The objectives and other advantages of the invention will be realizedand attained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

[0017] To achieve these objects and other advantages and in accordancewith the purpose of the invention, as embodied and broadly describedherein, an apparatus for manufacturing a liquid crystal display deviceincludes a vacuum processing chamber having a substrate entrance, anupper stage and a lower stage provided at an interior of the vacuumprocessing chamber, and a compensation system positioned within thevacuum processing chamber for compensating for a temperature loss of thevacuum processing chamber when a pressure in the interior of the vacuumprocessing chamber is reduced.

[0018] In another aspect, a method for manufacturing a liquid crystaldisplay device includes steps of loading first and second substratesinside a vacuum processing chamber, reducing a pressure in an interiorof the vacuum processing chamber, compensating for a temperature changein the vacuum processing chamber, bonding the first and secondsubstrates together, venting the vacuum processing chamber, andunloading the first and second substrates from the interior of thevacuum processing chamber.

[0019] It is to be understood that both the foregoing generaldescription and the following detailed description of the presentinvention are exemplary and explanatory and are intended to providefurther explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are included to provide afurther understanding of the invention and are incorporated in andconstitute a part of this specification, illustrate embodiments of theinvention and together with the description serve to explain theprinciple of the invention. In the drawings:

[0021]FIG. 1A is a cross sectional view of a substrate bonding deviceaccording to the related art during a loading process;

[0022]FIG. 1B is a cross sectional view of the substrate bonding deviceaccording to the related art during a bonding process;

[0023]FIG. 2 is a perspective view of a receiving system according tothe related art;

[0024]FIG. 3 is a cross sectional view of an exemplary substrate bondingapparatus during a loading process according to the present invention;

[0025]FIG. 4 is a cross sectional view of the exemplary substratebonding apparatus during a pressure reduction process according to thepresent invention;

[0026]FIG. 5 is a cross sectional view of the exemplary substratebonding apparatus during a bonding process according to the presentinvention;

[0027]FIG. 6 is a cross sectional view of another exemplary substratebonding apparatus according to the present invention;

[0028]FIG. 7 is a cross sectional view of another exemplary substratebonding apparatus according to the present invention;

[0029]FIG. 8 is a schematic diagram of an exemplary temperaturecompensating system according to the present invention;

[0030]FIG. 9 is a flow chart of an exemplary bonding process of an LCDdevice according to the present invention;

[0031]FIGS. 10A to 10J are cross sectional diagrams of an exemplarymanufacturing processes of an LCD device based on a liquid crystaldropping method according to the present invention; and

[0032]FIG. 11 is a graph of temperature change versus time duringpressure reduction of a vacuum processing chamber according to thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

[0033] Reference will now be made in detail to the preferred embodimentsof the present invention, examples of which are illustrated in theaccompanying drawings.

[0034]FIG. 3 is a cross sectional view of an exemplary substrate bondingapparatus during a loading process according to the present invention.In FIG. 3, the substrate bonding device may include a vacuum processingchamber 110, an upper stage 121, a lower stage 122, a stage movingsystem, a vacuum device 200, and a temperature compensating system.

[0035] In the vacuum processing chamber 110, a process of bonding afirst substrate 510 and a second substrate 520 may be performed. Thevacuum processing chamber 110 may be formed a single unit.Alternatively, the vacuum processing chamber 110 may be formed ofmultiple separate units. For example, the vacuum processing chamber 110may include upper and lower portions, wherein one or both of the upperand lower portions may move along vertical and horizontal directions.The vacuum processing chamber 110 may include an entrance 111 to allowfor introduction and extraction of the first and second substrates 510and 520 by a loading/unloading system 400. In addition, the vacuumprocessing chamber 110 may include an air outlet pipe 112 and a ventpipe 113. The air outlet pipe 112 may function to remove ambient airfrom an interior of the vacuum processing chamber 110 by the vacuumdevice 200, thereby reducing pressure of the interior of the vacuumprocessing chamber 110. The vent pipe 113 may function to supply theinterior of the vacuum processing chamber 110 with air and/or gas inorder to return the interior of the vacuum processing chamber 110 to anatmospheric pressure.

[0036] The air outlet pipe 112 and the vent pipe 113 may respectivelyinclude valves 112 a and 113 a that may be electronically or manuallycontrolled for selectively opening and closing pathways of the airoutlet and vent pipes 112 and 113.

[0037] Upper and lower parts of the vacuum processing chamber 110 mayinclude the upper and lower stages 121 and 122. The upper and lowerstages 121 and 122 may affix the first and second substrates 510 and 520brought into a vacuum processing chamber 110 by an loading/unloadingsystem 400. Accordingly, the upper stage 121 may affix the secondsubstrate 520 using one of a vacuum chuck or an electrostatic chuck.Likewise, the lower stage 122 may affix the first substrate 510 usingone of a vacuum chuck or an electrostatic chuck. The upper and lowerstages 121 and 122 may move along upward and downward directions.

[0038] A stage moving system may be coupled to the upper stage 121 andmay include a moving axis 131, a rotational axis 132, and a drivingmotor 133. The moving axis 131 may function to move the upper stage 121along the upward and downward directions. The rotational axis 132 mayfunction to move the lower stage 122 along the upward and downwarddirections as well as rotate the lower stage 122 about the upward anddownward directions. The driving motor 133 may function to move and/orrotate the respective axes provided to the upper and lower stages 121and 122.

[0039] The temperature compensating system may include heater elements310 for heating interior and/or exterior wall surfaces of the vacuumprocessing chamber 110. The temperature compensating system maycompensate for any temperature loss of the vacuum processing chamber 110when the pressure in the interior of the vacuum processing chamber 110is reduced. The heater elements 310 may be formed to contact theinterior and/or the exterior surfaces of the vacuum processing chamber110, thereby delivering hear to the interior of the vacuum processingchamber 110. Alternatively, the heater elements 310 may be formed onlyon the interior surface of the vacuum processing chamber 110, therebypreventing any interference with the exterior of the vacuum processingchamber 110. Accordingly, heat delivering pathways 320 may be formedalong the interior surfaces of the vacuum processing chamber 110, inwhich the heater elements 310 are provided.

[0040] The heater elements 310 may include a coil, strip, or radiantheaters. In addition, the heat delivering pathways 320 may be formedwithin sidewalls of the vacuum processing chamber 110, thereby uniformlydelivering heat to the interior of the vacuum processing chamber 110.Accordingly, a plurality of heat delivering pathways 320 may be formedwithin each of the sidewalls of the vacuum processing chamber 110.Alternatively, a single heat delivering pathway 320 may be formed alongall of the sidewalls of the vacuum processing chamber 110. Moreover,each of the sidewalls of the vacuum processing chamber 110 may include asingle heat delivering pathway 320, or only selected sidewalls mayinclude heat delivering pathways 320. Accordingly, the heat deliveringpathways 320 should be configured to deliver an adequate amount of heatto inlet parts of the heater elements 310. Thus, the interiortemperature of the vacuum processing chamber 110 should be compensatedso as not to drop below 0° C., thereby preventing condensation of theambient air or moisture within the liquid crystal material.

[0041] An exemplary process of bonding substrates using the temperaturecompensating system according to the present invention will be describedwith regard to FIG. 3. In FIG. 3, the loading/unloading system 400 maybe provided from a previous processing stage with the first substrate510 and the second substrate 520 for introduction into the vacuumprocessing chamber 110. The second substrate 520 may be loaded onto theupper stage 121, and the first substrate 510 may be loaded onto thelower stage 122. Both the upper and lower stages 121 and 122 may includea vacuum chuck and an electrostatic chuck for affixing the first andsecond substrates 510 and 520. Accordingly, the second substrate 520 maybe loaded onto the upper stage 121 before loading of the first substrate510 on the lower stage 122 in order to prevent any contamination frombeing transferred from the second substrate 520 onto the first substrate510.

[0042] When the loading of the first and second substrates 510 and 520is completed, the entrance 111 of the vacuum processing chamber 110 maybe closed, thereby sealing the interior of the vacuum processing chamber110.

[0043]FIG. 4 is a cross sectional view of the exemplary substratebonding apparatus during a pressure reduction process according to thepresent invention. In FIG. 4, the vacuum device 200 is enabled to reducethe pressure in the interior of the vacuum processing chamber 110.Alternatively, a plurality of vacuum devices 200 may be used, therebydecreasing a total amount of time to reduce the pressure in the interiorof the vacuum processing chamber 110. During the pressure reductionprocess, the opening/closing valve 112 a provided in the air outlet pipe112 of the vacuum processing chamber 110 keeps the air outlet pipe 112opened. Accordingly, the reduced pressure generated from the vacuumdevice 200 is delivered to the interior of the vacuum processing chamber110 through the air outlet pipe 112, and the interior of the vacuumprocessing chamber 110 gradually reaches a vacuum state. However, whenthe vacuum processing chamber 110 reaches the vacuum state, thetemperature of the interior of the vacuum processing chamber abruptlydrops.

[0044] The heater elements 310 of the temperature compensating systemare enabled to generate heat, and begin the delivery of heat througheach of the heat delivering pathways 320 formed within the sidewalls ofthe vacuum processing chamber 110. Accordingly, the heat deliveredthrough each of the heat delivering pathways 320 prevents the ambientair and/or moisture within the liquid crystal material from beingcondensed.

[0045] Alternatively, the temperature compensating process of thetemperature compensating system may be performed simultaneously with thepressure reduction process of the vacuum processing chamber 110.However, the temperature of the interior of the vacuum processingchamber 110 decreases rapidly as the pressure is reduced. Accordingly,if the pressure reduction process is performed simultaneously with thetemperature compensating process, the temperature compensating processmay not be adequate to provide enough heat. Therefore, the temperaturecompensating process of the vacuum processing chamber 110 should bestarted before the pressure reduction process begins, and should becontinued until the vacuum processing chamber 110 reaches more than adesired temperature. Alternatively, the temperature compensating processmay be performed when the loading of the substrates is completed or whenthe interior of the vacuum processing chamber 110 is sealed.

[0046] When the pressure in the interior of the vacuum processingchamber 110 has been adequately reduced by the vacuum device 200, thevacuum device 200 is disabled and the opening/closing valve 112 a keepsthe air outlet pipe 112 closed.

[0047]FIG. 5 is a cross sectional view of the exemplary substratebonding apparatus during a bonding process according to the presentinvention. In FIG. 5, as the stage moving system is driven, the upperstage 121 is moved along the downward direction toward the lower stage122, thereby joining and bonding the first and second substrates 510 and520 together.

[0048]FIG. 6 is a cross sectional view of another exemplary substratebonding apparatus according to the present invention. In FIG. 6, thesubstrate bonding device may include a heater element 330 positioned atthe exterior of the vacuum processing chamber 110, and a plurality ofheating pipes 340 may be formed along the interior sidewalls surfaces ofthe vacuum processing chamber 110 for delivering the heat generated bythe heater 330 to the interior of the vacuum processing chamber 110.Accordingly, and adjoining part of the heating pipes 340 and the vacuumprocessing chamber 110 should be sealed. The heating pipes 340 mayinclude a material having a high heat conductivity, and may beconfigured as a solid bar shape and/or a solid plate shape.

[0049] Alternatively, the plurality of heating pipes 340 may be formedof individually controlled groups. For example, a first plurality ofheating pipes 340 may be formed along top and/or bottom portions of thevacuum processing chamber 110 and may be connected to a first heater330, and a second plurality of heating pipes 340 may be formed alonglateral side portions of the vacuum processing chamber 110 and may beconnected to a second heater 330. Moreover, multiple configurations maybe possible depending upon a desired amount of temperature compensationof the interior of the vacuum processing chamber 110.

[0050]FIG. 7 is a cross sectional view of another exemplary substratebonding apparatus according to the present invention. In FIG. 7, thesubstrate bonding device may include a heater 360 positioned at theexterior of the vacuum processing chamber 110, and a plurality of heatdelivering pipes 350 may be formed along the interior sidewall surfacesof the vacuum processing chamber 110 and connected to the heater 360.Alternatively, the plurality of heat delivering pipes 350 may be formedof individually controlled groups. For example, a first plurality ofheat delivering pipes 350 may be formed along top and/or bottom portionsof the vacuum processing chamber 110 and may be connected to a firstheater 360, and a second plurality of heat delivering pipes 350 may beformed along lateral side portions of the vacuum processing chamber 110and may be connected to a second heater 360. Moreover, multipleconfigurations may be possible depending upon a desired amount oftemperature compensation of the interior of the vacuum processingchamber 110.

[0051]FIG. 8 is a schematic diagram of an exemplary temperaturecompensating system according to the present invention. In FIG. 8, arotating fan 370 may be formed to circulate a hot fluid, such as air,gas or a liquid, through the heat delivering pipes 350 from the heater360. In other words, when the vacuum processing chamber 110 of thepresent invention reaches a desired vacuum state, the heater 360 may beenabled to heat the circulating fluid circulating through the heatdelivering pipes 350. Accordingly, the fluid heated by the heater 360flows through the heat delivering pipes 350 and is conducted into theinterior of the vacuum processing chamber 110. Likewise, the fluid isconducted out of the interior of the vacuum processing chamber 110 andis circulated back into the heater 360 for reheating of the fluid,thereby providing temperature compensation for the vacuum processingchamber 110.

[0052]FIGS. 9 and 10A to 10J are a flow chart and cross sectionaldiagrams of an exemplary bonding process of an LCD device according tothe present invention. In FIGS. 9 and 10A, a step 31S may includeproviding a first substrate 11 having a liquid crystal material 12deposited thereon, and a second substrate 13 have a sealant 14 depositedthereon. Alternatively, the first substrate 11 may have both the liquidcrystal material 12 and the sealant 14 deposited thereon, and the secondsubstrate 13 may not have either of the liquid crystal material 12 andthe sealant 14 deposited thereon. The first and second substrates 11 and13 may include a thin film transistor substrate and/or a color filtersubstrate. The second substrate 13 may be cleaned via an ultrasoniccleaner (USC) prior to deposition of the sealant 14, thereby removingcontaminate particles that may otherwise interfere with bonding of thesealant 14. Likewise, the first substrate 11 may be cleaned using theUSC prior to deposition of the liquid crystal material 12.

[0053] In FIGS. 9 and 10B, a step 32S may include enabling a temperaturecompensating system at the interior of the vacuum processing chamber 10to compensate for a reduction of temperature of the interior of thevacuum processing chamber 10. Accordingly, although the vacuumprocessing chamber 10 maintains an ambient room temperature of about 23°C.˜25° C. at both an atmospheric state and a loading state, thetemperature of the vacuum processing chamber 10 rapidly drops when thevacuum processing chamber 10 reaches a desired vacuum state. When thetemperature of the vacuum processing chamber is below 0° C., anymoisture of the ambient air or gases of the vacuum processing chamber 10or any moisture contained in the liquid crystal material 12 (in FIG.10A) may be condensed. Accordingly, as shown in FIG. 10B, at the sametime as or before loading of the first and second substrates 11 and 13(in FIG. 10A) begins, compensation of the interior temperature of thevacuum processing chamber 10 may be enabled.

[0054] An exemplary timing sequence for the temperature compensatingprocess may begin during the loading of the first and second substrates11 and 13 (in FIG. 10A). In addition, to maximize loading efficiency,the temperature compensating process can be started after the loadingprocess is completed and before a pressure reduction process is started.Here, the temperature may be more easily compensated when aloading/unloading entrance of the vacuum processing chamber 10 isclosed. Moreover, to save overall processing time, the temperaturecompensating process can be started at the same time as or after thepressure reduction process is started. The temperature of the vacuumprocessing chamber may be compensated so as not to be dropped to or lessthan 0° C. Specifically, the interior temperature of the vacuumprocessing chamber 10 should be compensated to be at least 5° C. higherthan an ambient temperature of the exterior of the vacuum processingchamber 10. In addition, when considering possible differenttemperatures in different places in the interior of the vacuumprocessing chamber 10, the temperature may be compensated to be higherthan 35° C.-45° C.

[0055] In FIGS. 9 and 10C, a step 33S may include affixing a firstsurface of the second substrate 13 to an upper stage 15 of the vacuumprocessing chamber 10 by an electrostatic chuck such that as secondsurface of the second substrate 13, which has the sealant 14 appliedthereto, facing down toward a lower stage 16. Then, a step 34S mayinclude affixing a first surface of a first substrate 11, which has asecond surface having the liquid crystal 12, onto the lower stage 16 byanother electrostatic chuck. During both steps 33S and 34S, the vacuumprocessing chamber 10 may be maintained at the atmospheric state.

[0056] Specifically, steps 33S and 34S may include a loading/unloadingsystem (not shown) that introduces the second substrate 13 to theinterior of the vacuum processing chamber 10. Then, the upper stage 13travels along a downward direction toward the lower stage 16 to affixthe second substrate 13 to the upper stage 15 by the electrostaticchuck. After affixing the second substrate 13, the upper stage 15travels along an upward direction away from the lower stage 16. Inaddition, a vacuum chuck may be used instead of the electrostatic chuck.The loading/unloading system exits the vacuum processing chamber 10 andplaces the first substrate 11 on an upper side of the lower stage 16 inthe vacuum processing chamber 10.

[0057] In FIG. 9, a step 35S may include the loading/unloading systemplacing a substrate receiver (not shown) of the vacuum processingchamber 10 under the second substrate 13 that is affixed to the upperstage 15. The substrate receiver may be placed under the secondsubstrate 13 since magnitude of the vacuum pressure at the interior ofinside the vacuum processing chamber may be higher than a magnitude ofthe vacuum pressure of the vacuum chucks of the upper and lower stages.In other words, since the vacuum chucks of the upper and lower stages 15and 16 operate using a relatively lower degree of vacuum pressure and asthe vacuum processing chamber reaches the desired vacuum state, thefirst and second substrates 11 and 13 will become dislodged from theupper and lower stages 15 and 16. Thus, the substrate receiver may beplaced under the second substrate 13 to prevent the second substratefrom being detached from the upper stage and dropped onto the firstsubstrate 11. Then, the second substrate 13 may be later re-affixed tothe upper stage 15 using an electrostatic chuck. Likewise, the firstsubstrate 11 may be later re-affixed to the lower stage using anelectrostatic chuck.

[0058] In FIGS. 9 and 10D, a step 36S may include closing the chamberentrance (not shown) of the vacuum processing chamber 10, therebysealing the vacuum processing chamber 10. Then, a vacuum pump may beenabled to reduce the pressure in the interior of the vacuum processingchamber 10. The degree of vacuum pressure of the vacuum processingchamber 10 may be different according to a desired mode of operation ofthe liquid crystal display device. In the IPS mode, the degree of vacuumpressure may be from about 1.0×10⁻³ Pa to about 1 Pa. In the TN mode,the degree of vacuum pressure may be from about 1.1×10⁻³ Pa to about 10²Pa.

[0059] In FIGS. 9 and 10E, a step 37S may include re-affixing the secondsubstrate 13 to the upper stage 15 using the electrostatic chuck, andre-affixing the first substrate 11 to the lower stage 16 using theelectrostatic chuck. A step 38S may include returning the substratereceiver to its original position. In the electrostatic chucks, at leasttwo flat electrodes may be provided within each of the upper and lowerstages 15 and 16. Accordingly, anode/cathode direct current power may beapplied to each of the flat electrodes, and anode or cathode chargesflow to the stage. Thus, an electric conduction layer (i.e., atransparent layer such as a common electrode or a pixel electrode)formed on the first and second substrates 11 and 13 provide a necessarycoulomb force between the electric conduction layer and the electrodes.For example, if one of the substrate surfaces having the electricconduction layer is placed to face one of the stages, a voltage of about0.1 to 1KV is applied to the electrodes. Likewise, if another surface ofone of the substrates without the electric conduction layer is placed toface one of the stages, a voltage of about 3 to 4 KV is applied to theelectrodes. In order to prevent scratching of the substrates, an elasticsheet can be formed on the stages.

[0060] In FIGS. 9, 10E, and 10F, a step 39S may include aligning thefirst and second substrates 11 and 13 along a horizontal direction.Specifically, the upper stage 15 is lowered along the downward directionuntil a first interval of about 0.4 mm˜0.9 mm between the first andsecond substrates 11 and 13 is maintained. Then, a first alignment checkmay be performed using a first set of alignment marks positioned on boththe first and second substrates 11 and 13. Accordingly, alignment of thefirst and second substrates 11 and 13 may be performed using the stagemoving system, as shown in FIG. 3, for the upper stage 15, and/or therotational axis 132, as shown in FIG. 3, for the lower stage 16. Next,as shown in FIG. 10F, the upper stage 15 may travel along the downwarddirection until a second interval of about 0.1 mm˜0.4 mm between thefirst and second substrates 11 and 13 is maintained. Then, a secondalignment check may be performed using a second set of alignment markspositioned on both the first and second substrates 11 and 13.Alternatively, the first set of alignment marks instead of, or inaddition to the second set of alignment marks may be used during thesecond alignment check. Accordingly, further alignment of the first andsecond substrates 11 and 13 may be performed using the stage movingsystem, as shown in FIG. 3, for the upper stage 15, and/or therotational axis 132, as shown in FIG. 3, for the lower stage 16. Thus,the first and second substrates 11 and 13 are aligned.

[0061] In FIGS. 9, 10G, and 10H, a step of 40S may include the upperstage 15 traveling along the downward direction to join the first andsecond substrates 11 and 13. Then, the upper stage 15 and/or the lowerstage 16 travels to further bond the first and second substrates 11 and13 together. The speed at which the upper and/or lower stages 15 and 16move, and the resulting degree of applied pressure may be different. Forexample, a first point of time may be defined when the second substrate13 contacts the liquid crystal material 12 of the first substrate 11, orwhen the first substrate 11 contacts the sealant 14 of the secondsubstrate. Then, after the first point of time until a final pressuretime, the applied pressure increases by stages incrementally. Forexample, the first and second substrates 11 and 13 may be bondedtogether by about 0.1 tons of pressure during the first point of time.Next, the first and second substrates 11 and 13 may be bonded togetherby about 0.3 tons of pressure at a second point of time. Then, the firstand second substrates 11 and 13 may be bonded together by about 0.4 tonsof pressure at a third point of time. Finally, the first and secondsubstrates 11 and 13 may be bonded together by about 0.5 tons ofpressure at a fourth point of time, as shown in FIG. 10H. The pressureis applied such that air or gases do not flow into the interval of thetwo bonded substrates.

[0062] In FIGS. 9 and 10I, a step 41S may include stopping the bondingprocess when the first and second substrates are completely bonded.Next, the electrostatic chuck of both the upper and lower stages 15 and16 are disabled, thereby releasing the bonded substrates. Then, theupper stage 15 is moved along the upward direction.

[0063] In FIGS. 9 and 10J, a step 42S may include venting the vacuumprocessing chamber 10 to supply nitrogen gas and dry air into theinterior of the vacuum processing chamber 10, therey restoring thepressure of the interior of the vacuum processing chamber 10 to anatmospheric state. Accordingly, the bonded first and second substrates11 and 13 are pressured by a constant degree of pressure so that thesubstrates maintain an even interval therebetween.

[0064] During the step 42S, the two substrates are evenly pressured, andthe sealant disposed between the bonded first and second substrates 11and 13 is formed with a constant height and thickness. In addition, theresulting interval between the bonded substrates may be 5 mm or less.Specifically, during the bonding process in the interior of the vacuumprocessing chamber 10, if the sealant is formed to a height range ofabout 35˜45 μm, the interval between the substrates may be within therange of 25˜35 μm. Then, when the venting process is performed, theinterval between the bonded substrates wherein the sealant is disposedis reduced to about 6 μm or less, and the interval wherein the liquidcrystal material is disposed is about 5 μm or less.

[0065] In FIGS. 9 and 10J, a step 43S may include unloading the bondedsubstrates. Specifically, when the interior pressure of the vacuumprocessing chamber 10 has reached the atmospheric state, the bondedsubstrates 11 and 13 may be removed from the vacuum processing chamber10 by the loading/unloading system (not shown). Alternatively, thebonded substrates 11 and 13 may be affixed to the upper stage 15 via thevacuum chuck or the electrostatis chuck, and may travel along the upwarddirection. Then, the loading/unloading system may be position beneaththe upper stage 15, and the bonded substrates 11 and 13 may be loweredonto the loading/unloading system from the upper stage 15. Finally, thevacuum chuck or the electrostatic chuck may be disabled, and the bondedsubstrates 11 and 13 transferred onto the loading/unloading system andremoved from the interior of the vacuum processing chamber 10.

[0066] In order to reduce an overall processing time, one of thefollowing methods may be applied. First, during a subsequent bondingprocess of new first and new second substrates, the new second substratemay be placed onto the upper stage 15 by the loading/unloading systemand affixed to the upper stage 15 by the vacuum chuck. Then, the bondedsubstrates that remain on the lower stage 16 may be unloaded.Alternatively, the upper stage 15 may travel along the upward directionwith the bonded substrates 11 and 13 affixed via the vacuum chuck, and anew first substrate 11 may be loaded onto the lower stage 16. Then, andthe upper stage 15 may be moved along the downward direction, and thebonded substrates 11 and 13 may be transferred onto theloading/unloading system.

[0067] The temperature compensating system may be enabled at the sametime as or prior to the loading process, and stopped before the ventingprocess is started. Accordingly, the vacuum processing chamber 10 may beheated to a temperature of about 5° C. higher than the ambient roomtemperature, which may be about 23˜25° C.

[0068] It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present invention. Thus,it is intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. An apparatus for manufacturing a liquid crystaldisplay device, comprising: a vacuum processing chamber having asubstrate entrance; an upper stage and a lower stage provided at aninterior of the vacuum processing chamber; and a compensation systempositioned within the vacuum processing chamber for compensating for atemperature loss of the vacuum processing chamber when a pressure in theinterior of the vacuum processing chamber is reduced.
 2. The apparatusaccording to claim 1, wherein the compensation system is provided on oneof an upper surface and a lower surface of the interior of the vacuumprocessing chamber.
 3. The apparatus according to claim 1, wherein thecompensation system includes at least one heat system for heating innersurfaces of the interior of the vacuum processing chamber.
 4. Theapparatus according to claim 3, wherein the heat system is providedalong the inner surfaces of the interior of the vacuum processingchamber.
 5. The apparatus according to claim 3, wherein the heatingsystem includes coil heaters.
 6. The apparatus according to claim 1,wherein the compensation system includes at least one heat system forheating outer surfaces of an exterior of the vacuum processing chamber.7. The apparatus according to claim 6, wherein the heating system isprovided on the outer surfaces of the exterior of the vacuum processingchamber.
 8. The apparatus according to claim 6, wherein the heatingsystem includes coil heaters.
 9. The apparatus according to claim 1,wherein the compensation systems includes external heaters, and heatingpipes formed along inner surfaces of the interior of the vacuumprocessing chamber.
 10. The apparatus according to claim 1, wherein thecompensation system includes heaters for heating a fluid, and aplurality of heat delivering pipes being formed along within sidewallsof the vacuum processing chamber.
 11. A method for manufacturing aliquid crystal display device, comprising the steps of: loading firstand second substrates inside a vacuum processing chamber; reducing apressure in an interior of the vacuum processing chamber; compensatingfor a temperature change in the vacuum processing chamber; bonding thefirst and second substrates together; venting the vacuum processingchamber; and unloading the first and second substrates from the interiorof the vacuum processing chamber.
 12. The method according to claim 11,wherein the step of loading includes absorbing the second substrate ontoan upper stage and absorbing the first substrate onto a lower stagewithin the vacuum processing chamber, placing a substrate receiver intothe interior of the vacuum processing chamber and under the secondsubstrate absorbed onto the upper stage, affixing the second substrateonto the upper stage by a first electrostatic chuck, and affixing thefirst substrate by a second electrostatic chuck.
 13. The methodaccording to claim 11, wherein the step of compensating is performedafter the step of loading and before the step of reducing a pressure.14. The method according to claim 11, further including a step ofclosing an entrance of the vacuum processing chamber after the step ofloading and before the step of compensating.
 15. The method according toclaim 11, wherein the step of compensating is performed at a same timeas the step of reducing a pressure.
 16. The method according to claim11, wherein the step of reducing a pressure is performed more than once.17. The method according to claim 11, wherein the step of reducing apressure includes steps of: absorbing and affixing the first substrateonto the lower stage; absorbing and affixing the second substrate ontothe upper stage; reducing the pressure of the interior of the vacuumprocessing chamber for a first time; placing the substrate receiverunder the second substrate absorbed onto the upper stage, and reducingthe pressure of the vacuum processing chamber for a second time.
 18. Themethod according to claim 11, further including a step of aligning thefirst and second substrates after the step of reducing a pressure andbefore the step of bonding.
 19. The method according to claim 11,wherein the step of compensating for a temperature change includesincreasing a temperature of the interior of the vacuum processingchamber to more than about 5° C. above room temperature.
 20. The methodaccording to claim 11, wherein, the step of compensating includesincreasing a temperature of the interior of the vacuum processingchamber to more than about 35° C.
 21. The method according to claim 11,wherein the step of compensating includes increasing a temperature ofthe interior of the vacuum processing chamber to more than about 45° C.22. The method according to claim 11, wherein the step of compensatingincludes maintaining a temperature of the interior of the vacuumprocessing chamber at greater than 0° C.